if jets are producing too much green house gas which aircraft apart from gliders is most eficient?

Question

is there acomparison between the cars emition and human respiration

Answer 1

The most efficient powered aircraft in terms of miles traveled per unit of CO2 exhausted is a low speed, high lift aircraft with a conventional propeller. As the speed of the aircraft increases the use of propellors becomes more limited and jet propulsion becomes more attractive. The most efficent form of jet in use today is the turbo-prop, but this is also limited to speeds not much exceeding sound (Mach 1). To exceed Mach 1 conventional jets are required today.

However, it is not the type of engine that determines the CO2 output, it is the fuel. For example, a fuel of liquid hydrogen would emit no greenhouse gas at all, the exhaust would be pure water vapor. This is not done today because of the difficulty of packaging and handling liquid hydrogen (it must be kept cold or under high pressure, and leaks through exceedingly small openings). The widespread concern regarding global warming is making hydrogen more attractive as a fuel and many are working on the problems.

As an interesting aside, jet exhaust, although a strong contributor to greenhouse gases, may actually reduce global warming. This is because the jet plumes are very effective in forming the nucleii
of clouds and clouds increase the "albedo" of the atmosphere, reflecting sunlight back out into space. For most of us, reducing warming by making the sky cloudy does not seem a good idea.

Answer 2

CO2 is just that it makes no difference. CO2 is not a green house gas ,but the first step in the earth's air recycling. Plants have done a great Job.Look it up on the net photosynthesis.

Answer 3

My little single engine airplane sips fuel at the minuscule rate of about 10.5 gallons per hour. At 190 knots TAS (true air speed) this gives me a mileage rating of about 20 miles per gallon or a cost of about $ .096 per seat mile.

I have no idea what the second part of your question asks.